A typical three-point safety seat belt system for use in a vehicle includes belt webbing having one end secured to the vehicle. The belt webbing is guided through a D-shaped ring secured to the vehicle, and the other end of the belt webbing is connected to a seat belt retractor secured to the vehicle. The seat belt retractor includes a spool on which the belt webbing is wound and from which the belt webbing is withdrawn. The belt webbing is slidable through the D-shaped ring as the belt webbing is wound onto the spool or withdrawn from the spool. A buckle tongue is carried by and slidable on the belt webbing. The tongue is latchable with a belt buckle fixed to the vehicle. When the tongue is latched with the belt buckle, the belt webbing is divided into a lap belt portion and a shoulder belt portion.
When it is desired to use a child's seat in the vehicle, the child's seat is first placed on a vehicle seat. The lap belt portion of the belt webbing is extended around the child's seat and the adjust tongue is latched with the belt buckle. The lap belt portion bears on the child's seat to secure the child's seat on the vehicle seat.
In a conventional three-point safety seat belt system, the belt webbing may be able to slide relative to the tongue even though the tongue is latched with the belt buckle. Sliding of the belt webbing relative to the adjust tongue may result in loosening of the lap belt portion about the child's seat. If the lap belt portion loosens about the child's seat, the child's seat may move relative to the vehicle seat.
There are known ways to restrict sliding of the belt webbing relative to the tongue when the lap belt portion of the belt webbing is used to secure the child's seat on a vehicle seat. One way is to use a second locking tongue in addition to the tongue which is latched with the belt buckle as disclosed in U.S. Pat. No. 4,685,740 to Fohl. The additional tongue permits tightening of the lap belt portion and resists loosening of the lap belt portion. The additional cost is a drawback in using an additional adjust tongue in a conventional three-point safety seat belt system.
Another known way to restrict sliding of the belt webbing relative to the tongue when a child's seat is secured on the vehicle seat is to use a known clip for securing the lap belt portion of the belt webbing to the shoulder belt portion of the belt webbing. The clip preferably is made from stamped metal and includes a pair of C-shaped end portions connected by a central bar. To use the clip, the lap and shoulder belt portions are overlapped and manipulated so that the belt portions are trained through the clip and around the bar. Tension on the belt causes the belt portions to be secured together and relative movement of the belt portions is restricted. Thus, the child's seat is secured on the vehicle seat.